1. Field of the Disclosure
Embodiments disclosed herein relate generally to rock drilling operations. More particularly, embodiments disclosed herein relate to air filtration devices used in water injected dust suppression devices for rock drilling operations.
2. Background Art
Drilling into rock formations to enable explosive charges to be placed for excavating ore in open-cut mining operations may be carried out by rotary air blast drills. Air at high pressure (typically 40 psi) and volume (750 to 2000 cubic feet a minute (cfm)) may be delivered through a bore in the drill string to the drill bit. The air supplied to the drill bit, which may for example be a blade or roller type bit, exits from orifices or nozzles in the bit, cools the bearings of the bit and conveys the debris created by the drilling away from the drilling workface up the borehole. This debris may travel up the borehole at a typical (bailing) velocity of 5,000 to 7,000 feet per minute depending on the size of the borehole and the drill string.
The debris produced may include particulate matter and dust. To reduce the dispersion of dust into the environment, which may have deleterious effects on equipment and personnel, the debris is sprayed with water. The water may be supplied with the air through the drillstring to the drill bit and in addition to suppressing dust, may also cause accelerated bearing failure. This is because the air being sent via the drillstring, in an open air bearing rotary tool, is used to cool the bearings as well as flush out cuttings within the bearing because there is no sealing system. As a result of now introducing water with the air via the drillstring, the bearing life may be reduced. Some of the potential failure modes by having water in the bearing may include an increased potential for spalling, hydrogen embrittlement, or accelerated wear of the components. Accordingly, there exists a need for a device capable of reducing or preventing water into air-driven rotary tools.